Intestinal Absorption of Botulinum Toxins of Different Molecular Sizes in Rats

Abstract

During a period of 10 to 12 h after injection of type B 16S (L) toxin into the ligated duodenum of rats, 0.01 to 0.1% of the total toxicity administered was found in the lymph drawn by cannulation of the thoracic duct. The recovery was 50 to 100 times higher than that of the rat given type B 12S (M) or 7S (S) toxin. During the same period, 0.6 to 1.5% of the specific antigens were recovered, regardless of the molecular size of the toxin that had been administered. In lymph of the B-L or B-M toxin recipient, the toxic and nontoxic components were detected in comparable quantities, indicating that the undissociated progenitor toxin molecule is absorbed through the intestinal wall. Although the toxic component had lost its toxic activity, the two components of B-M toxin appearing in lymph reassembled to reconstruct the 12S molecule, whereas those of B-L toxin did not, although the toxic component was still active. Type B-L, B-M, and B-S toxins showed similar stabilities to in vitro exposure to rat lymph (pH 8.2), but B-L toxin showed a considerably higher stability to intestinal juice (pH 7.0) than did B-M toxin. Thus, the toxicity of lymph of rats administered botulinum toxin intraduodenally depends not upon the rate of absorption, but largely upon the stability in the intestine.

Receptor-mediated transcytosis of botulinum neurotoxin A through intestinal cell monolayers

“…It is noteworthy that the in vivo transport of BoNT through the intestinal barrier is also low. Indeed, the transport rate of BoNT/B from rat duodenum to the lymphatic circulation has been estimated from 0.01% to 0.1% (Sugii et al, 1977). Thereby, transcytosis of BoNT/A in experimental intestinal barrier was low, but in the same range as that of enteric pathogens or that of BoNT in the in vivo model.…”

The Convergence of Medicine and Neurotoxins: A Focus on Botulinum Toxin Type A and Its Application in Aesthetic Medicine—A Global, Evidence-Based Botulinum Toxin Consensus Education Initiative

“…This structure appears to have a protective function after ingestion, shielding the neurotoxin from acidic stomach conditions and thermal and pH stress. [8][9][10] It has also been suggested that the natural complex acts as a shield for the antigenic epitopes on the 150-kD heavy chain 11 and facilitates BoNTA transfer across the intestinal epithelium. [12][13][14][15] In medicine, the effect and role of the complex's size and composition are not clear and remain controversial.…”

Translocation and dissemination to target neurons of botulinum neurotoxin type B in the mouse intestinal wall

“…Previous observations using experimental models of animal intoxination have shown that following oral administration, BoNT enters the blood stream and lymph circulation (Maksymowych et al, 1999). The upper small intestine was found to be the primary site of toxin absorption (Kitamura et al, 1969;Sugii et al, 1977;Bonventre, 1979;Fujinaga et al, 1997). However, BoNT can also be absorbed from the other parts of the digestive tract including the buccal cavity, stomach and colon, but to a lower extent than in the upper small intestine (Bonventre, 1979;Sakaguchi, 1983;Maksymowych et al, 1999).…”